Method of making a multi-phase aggregate using a multi-stage process

ABSTRACT

Elastomeric compositions are described and include at least one elastomer and an aggregate having a carbon phase and a silicon-containing species phase. The aggregate exhibits one or more specific characteristics. Methods of improving the rolling resistance of an elastomeric composition are also described and include introducing the aggregate into an elastomeric composition.

This application is a divisional of U.S. application Ser. No.09/061,871, filed Apr. 17, 1998 now U.S. Pat. No. 6,057,387 which inturn is a Continuation-In-Part of U.S. application Ser. No. 08/837,493,filed Apr. 18, 1997, now U.S. Pat. No. 5,904,762, which is incorporatedin its entirety by reference herein.

FIELD OF THE INVENTION

The present invention relates to a method of making an aggregate using amulti-stage process. In particular, the process relates to a method ofmaking an aggregate comprising at least a carbon phase and asilicon-containing species phase using a multi-stage reactor. Thepresent invention also relates to a method of making an aggregatecomprising a carbon phase and a metal-containing species phase. Thepresent invention in addition relates to the use of one or more of theseaggregates in compositions such as elastomeric compositions and furtherrelates to methods to improve rolling resistance and wet traction fortire compounds and relates to elastomeric compositions having theseproperties.

BACKGROUND OF THE INVENTION

Carbon blacks are widely used as pigments, fillers, and reinforcingagents in the compounding and preparation of rubber and otherelastomeric compounds. Carbon blacks are particularly useful asreinforcing agents in the preparation of elastomeric compounds used inthe manufacture of tires.

Carbon blacks are generally produced in a furnace-type reactor bypyrolyzing a hydrocarbon feedstock with hot combustion gases to producecombustion products containing particulate carbon black. Carbon blackexists in the form of aggregates. The aggregates, in turn are formed ofcarbon black particles. However, carbon black particles do not generallyexist independently of the carbon black aggregate. Carbon blacks aregenerally characterized on the basis of analytical properties,including, but not limited to, particle size and specific surface area;aggregate size, shape, and distribution; and chemical and physicalproperties of the surface. The properties of carbon blacks areanalytically determined by tests known to the art. For example, nitrogenadsorption surface area (measured by ASTM test procedure D3037-Method Aor D4820-Method B) and cetyl-trimethyl ammonium bromide adsorption value(CTAB) (measured by ASTM test procedure D3765 [09.01]), are measures ofspecific surface area. Dibutylphthalate absorption of the crushed (CDBP)(measured by ASTM test procedure D3493-86) and uncrushed (DBP) carbonblack (measured by ASTM test procedure D2414-93), relates to theaggregate structure. The bound rubber value relates to the surfaceactivity of the carbon black. The properties of a given carbon blackdepend upon the conditions of manufacture and may be modified, e.g., byaltering temperature, pressure, feedstock, residence time, quenchtemperature, throughput, and other parameters.

It is generally desirable in the production of tires to employ carbonblack-containing compounds when constructing the tread and otherportions of the tire. For example, a suitable tread compound will employan elastomer compounded to provide high abrasion resistance and goodhysteresis balance at different temperatures. A tire having highabrasion resistance is desirable because abrasion resistance isproportional to tire life. The physical properties of the carbon blackdirectly influence the abrasion resistance and hysteresis of the treadcompound. Generally, a carbon black with a high surface area and smallparticle size will impart a high abrasion resistance and high hysteresisto the tread compound. Carbon black loading also affects the abrasionresistance of the elastomeric compounds. Abrasion resistance increaseswith increased loading, at least to an optimum point, beyond whichabrasion resistance actually decreases.

The hysteresis of an elastomeric compound relates to the energydissipated under cyclic deformation. In other words, the hysteresis ofan elastomeric composition relates to the difference between the energyapplied to deform the elastomeric composition and the energy released asthe elastomeric composition recovers to its initial underformed state.Hysteresis is characterized by a loss tangent, tan δ, which is a ratioof the loss modulus to the storage modulus (that is, viscous modulus toelastic modulus). Tires made with a tire tread compound having a lowerhysteresis measured at higher temperatures, such as 40° C. or higher,will have reduced rolling resistance, which in turn, results in reducedfuel consumption by the vehicle using the tire. At the same time, a tiretread with a higher friction coefficient on a wet surface will result ina tire with high wet traction and wet skid resistance which willincrease driving safety. Thus, a tire tread compound demonstrating lowhysteresis at high temperatures and high hysteresis at low temperaturescan be said to have a good hysteresis balance.

There are many other applications where it is useful to provide anelastomer exhibiting a good hysteresis balance but where the abrasionresistance is not an important factor. Such applications include but arenot limited to tire components such as undertread, wedge compounds,sidewall, carcass, apex, bead filler and wire skim; engine mounts; andbase compounds used in industrial drive and automotive belts.

Silica is also used as a reinforcing agent (or filler) for elastomers.However, using silica alone as a reinforcing agent for elastomer leadsto poor performance compared to the results obtained with carbon blackalone as the reinforcing agent. It is theorized that strongfiller-filler interaction and poor filler-elastomer interaction accountsfor the poor performance of silica. The silica-elastomer interaction canbe improved by chemically bonding the two with a chemical couplingagent, such as bis (3-triethoxysilylpropyl) tetra-sulfane, commerciallyavailable as Si-69 from Degussa AG, Germany. Coupling agents such asSi-69 create a chemical linkage between the elastomer and the silica,thereby coupling the silica to the elastomer.

When the silica is chemically coupled to the elastomer, certainperformance characteristics of the resulting elastomeric composition areenhanced. When incorporated into vehicle tires, such elastomericcompounds provide improved hysteresis balance. However, elastomercompounds containing silica as the primary reinforcing agent exhibit lowthermal conductivity, high electrical resistivity, high density, andpoor processability.

When carbon black alone is used as a reinforcing agent in elastomericcompositions, it does not chemically couple to the elastomer but thecarbon black surface provides many sites for interacting with theelastomer. While the use of a coupling agent with carbon black mightprovide some improvement in performance to an elastomeric composition,the improvement is not comparable to that obtained when using a couplingagent with silica.

SUMMARY OF THE INVENTION

The present invention relates to a method of making an aggregatecomprising at least a carbon phase and a silicon-containing speciesphase. In the method, for a two stage feedstock injection system, afirst feedstock is introduced into a first stage of a multi-stagereactor. The first feedstock comprises a carbon black-yieldingfeedstock, a silicon-containing compound or a mixture thereof. Themethod further includes the step of introducing a second feedstock intothe reactor at a location downstream of the first stage. The secondfeedstock comprises a carbon black-yielding feedstock, asilicon-containing compound, or a mixture thereof, with theunderstanding that if the first feedstock comprises only a carbonblack-yielding feedstock (without a silicon-containing compound), thenthe second feedstock comprises either a mixture of a carbonblack-yielding feedstock and a silicon-containing compound orsilicon-containing compound alone. At least one feedstock, either thefirst feedstock or the second feedstock, comprises at least a carbonblack-yielding feedstock and at least one of the feedstocks, the firstor the second feedstock, comprises a silicon-containing compound.However, the number of stages can be any number but must be at leasttwo. The multi-stage reactor is maintained at a sufficient temperatureto decompose the silicon-containing compound and to pyrolize the carbonblack-yielding feedstock.

The present invention further relates to a method of making an aggregatecomprising a carbon phase and a silicon-containing species phase,wherein a multi-stage reactor is used having at least three stages forintroducing feedstocks into the reactor. The second and third stages aswell as any additional stages are located downstream of the first stage.Each of the feedstocks introduced into the stages comprises a carbonblack-yielding feedstock, a silicon-containing compound, or a mixturethereof. At least one of the stages comprises a carbon black-yieldingfeedstock and at least one of the stages comprises a silicon-containingcompound. The reactor is maintained at a sufficient temperature todecompose the silicon-containing compound and to pyrolize the carbonblack-yielding feedstock.

The aggregates of the present invention preferably have a rough surfacemeasured by the difference between BET (N₂) surface area and t-area ofthe aggregate. Upon HF (hydrofluoric acid) treatment, BET area andt-area of this aggregate preferably increases. The aggregate size afterHF treatment measured by DCP (Disc centrifuge photosedimentameter) maybe generally reduced, and a certain amount of silica remains in theaggregate. The silica remaining after thermal treatment of the carbonphase at 500° C. in air preferably has a high surface area.

In addition, the present invention relates to a method of making anaggregate comprising a carbon phase and a metal-containing species phasewherein a multi-stage reactor is used having at least two stages forintroducing feedstocks into the reactor. The second stage as well as anyadditional stages are located downstream of the first stage. Each of thefeedstocks introduced into the stages comprises a carbon black-yieldingfeedstock, a metal-containing compound, or a mixture thereof. One ormore of the feedstocks further optionally comprises a silicon-containingcompound. At least one of the stages comprises a carbon black-yieldingfeedstock and at least one of the stages comprises a metal-containingcompound. The reactor is maintained at a sufficient temperature todecompose the metal-containing compound and to pyrolize the carbonblack-yielding feedstock.

The aggregates made from the above-described methods can be incorporatedinto elastomeric compositions. These elastomeric compositions canprovide improved wet skid resistance and rolling resistance compared toelastomeric compositions not having any aggregates comprising a carbonphase and a silicon-containing species phase present.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are intended to provide further explanation of the presentinvention, as claimed. Additional features and advantages of the presentinvention will be set forth in part in the description which follows,and in part will be apparent from the description, or may be learnedfrom the description, or may be learned by practice of the presentinvention. The objectives and other advantages of the present inventionwill be realized and attained by means of the elements and combinationsparticularly pointed out in the written description and appended claims.

The accompanying drawing, which is incorporated in and constitutes apart of this specification, illustrates an embodiment of the presentinvention and together with the description, serves to explain theprinciples of the present invention.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE is a schematic view of a portion of one type of a multistagereactor which may be used to produce the aggregates of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the present invention is directed to a method ofmaking an aggregate comprising a carbon phase and a silicon-containingspecies phase. In addition to making an aggregate comprising a carbonphase and a silicon-containing species phase, the method of the presentinvention can optionally also produce carbon black and/or silica.

For purposes of the present invention, the aggregate comprising a carbonphase and a silicon-containing species phase and made from the processesof the present invention can also be identified as a silicon-treatedcarbon black. In the aggregate comprising a carbon phase and asilicon-containing species phase, a silicon-containing species,including but not limited to, oxides and carbides of silicon, may bedistributed through at least a portion of the aggregate and is anintrinsic part of the aggregate which also contains the carbon phase. Inother words, the silicon-treated carbon black or the aggregate does notrepresent a mixture of discrete carbon black aggregates and discretesilica aggregates. Rather, the silicon-treated carbon black of thepresent invention includes at least one silicon-containing region aspart of the silicon-treated carbon black wherein the silicon-containingregion is located at the surface of and/or within the silicon-treatedcarbon black. The silicon-containing species that is part of theaggregate of the present invention is not attached to a carbon blackaggregate like a silane coupling agent, but actually is part of the sameaggregate as the carbon phase. The disclosures of U.S. patentapplication Ser. No. 08/446,141, filed May 22, 1995, now allowed; Ser.No. 08/446,142, filed May 22, 1995; and Ser. No. 08/750,016 filed Nov.22, 1996, which is a National Phase application of PCT PublishedApplication No. WO 96/37547 are incorporated in their entirety herein byreference.

When the silicon-treated carbon black is examined under STEM-EDX, thesilicon signal corresponding to the silicon-containing species is foundto be present in individual carbon black aggregates. By comparison, forexample, in a physical mixture of silica and carbon black, STEM-EDXexamination reveals distinctly separate silica and carbon blackaggregates.

The aggregates preferably made with the processes of the presentinvention preferably lead to improved wet skid resistance and/or rollingresistance properties in an elastomeric composition when the aggregatesof the present invention are incorporated into the elastomericcomposition.

With regard to a process of the present invention, the aggregates or thesilicon-treated carbon blacks of the present invention may be obtainedby manufacturing or forming the carbon black (i.e., the carbon phase) inthe presence of one or more volatilizable and/or decomposablesilicon-containing compounds. A modular or “staged,” furnace carbonblack reactor as depicted in the FIGURE is preferably used. The furnaceor reactor preferably has more than one stage or entry point forfeedstocks. As depicted in the FIGURE, the reactor preferably has acombustion zone 1, with a zone of converging diameter 2; a feedstockinjection zone with restricted diameter 3; and a reaction zone 4.

To produce the aggregates or the silicon-treated carbon blacks of thepresent invention with the reactor described above, hot combustion gasesare generated in combustion zone 1 by contacting a liquid or gaseousfuel with a suitable oxidant stream such as air, oxygen, or mixtures ofair and oxygen. Among the fuels suitable for use in contacting theoxidant stream in combustion zone 1, to generate the hot combustiongases, are included any readily combustible gas, vapor, or liquidstreams such as natural gas, hydrogen, methane, acetylene, alcohols, orkerosene. It is generally preferred, however, to use fuels having a highcontent of carbon-containing components and in particular, hydrocarbons.The ratio of air-to-fuel varies with the type of fuel utilized. Whennatural gas is used to produce the carbon phase of the presentinvention, the ratio of air-to-fuel may be from about 10:1 to about1000:1. To facilitate the generation of hot combustion gases; theoxidant stream may be pre-heated. U.S. Pat. Nos. 3,952,087 and 3,725,103are incorporated in their entirety by reference and describe carbonblack-yielding feedstocks, reactor set-up, and conditions.

The hot combustion gas stream flows downstream from zones 1 and 2 intozones 3 and 4. The direction of the flow of hot combustion gases isshown in the FIGURE by the arrow. A first feedstock is introduced atlocation 6 and enters the feedstock injection zone 3 at entry point 9.In this embodiment, the feedstocks are introduced or injected into apreformed stream of hot combustion gasses flowing in a downstreamdirection. While the FIGURE depicts entry points 9 and 10 forintroduction of the feedstock, the feedstocks can be introduced at anypoint in the reactor as long as there is a sufficient temperature andresidence time for the silicon-treated carbon black to form before thequench location. The feedstock is injected into the gas streampreferably through nozzles designed for optimal distribution of the oilin the gas stream. Such nozzles may be either single or bi-fluid.Bi-fluid nozzles may use steam or air to atomize the fuel. Single-fluidnozzles may be pressure atomized or the feedstock can be directlyinjected into the gas stream. In the latter instance, atomization occursby the force of the gas stream.

In an embodiment of the present invention, the first feedstock comprisesa carbon black-yielding feedstock, a silicon-containing compound, or amixture thereof. Also, the first feedstock, as well as all of thefeedstocks described hereinafter, may further comprise additionalmaterials or compositions which are commonly used to make conventionalcarbon black. One or more feedstocks can also contain a boron-containingcompound.

Located downstream of the point where the first feedstock is introducedinto the feedstock injection zone 3 of the reactor, a second feedstockis introduced, for example, through location 7 into the feedstockinjection zone 3. The second feedstock can enter the feedstock injectionzone for instance, at entry point 10. The second and subsequentfeedstocks are preferably added at the zone of substantial reaction,which is where the earlier feedstocks will primarily react to form theaggregates. The second feedstock comprises a carbon black-yieldingfeedstock, a silicon-containing compound, or a mixture thereof. As inthe case of the first feedstock, other additional compounds or materialscan also be included as part of the feedstock. Furthermore, the firstfeedstock and the second feedstock can be the same or different withrespect to feedstocks.

When a two-stage reactor is used, for purposes of an embodiment of thepresent invention, if the first feedstock contains a carbonblack-yielding feedstock (without a silicon-containing compound), thenthe second feedstock comprises either a mixture of a carbonblack-yielding feedstock and a silicon-containing compound or asilicon-containing compound alone. In other words, one or bothfeedstocks may contain a carbon black-yielding feedstock, and at leastone feedstock will additionally contain a silicon-containing compound.

In addition, additional feedstocks can be introduced into the feedstockinjection zone by additional entry points which can be locateddownstream of the first and/or second entry points for the first andsecond feedstocks. If necessary, a reactor can be modified to lengthenthe feedstock injection zone to accommodate the additional entry points.

For purposes of the present invention where a two-stage reactor is usedto make an aggregate comprises a carbon phase and a silicon-containingphase, at least one of the feedstocks must include a carbonblack-yielding feedstock and at least one of the feedstocks must containa silicon-containing feedstock. Thus, and only as an example, the firstfeedstock can include a mixture of a carbon black-yielding feedstock anda silicon-containing compound while the second feedstock can alsoinclude either a mixture of a carbon black-yielding feedstock and asilicon-containing compound or a silicon-containing compound only. Thefirst feedstock and the second feedstock can both include a carbonblack-yielding feedstock and the second feedstock can also include asilicon-containing compound. Accordingly, almost any combination offeedstocks is possible in the two-stage process as long as a carbonblack-yielding feedstock and a silicon-containing compound are presenteither in the same or different feedstocks. As stated earlier, in atwo-stage process, when the first feedstock comprises a carbonblack-yielding feedstock (without a silicon-containing compound), thenthe second feedstock comprises a mixture of a carbon black-yieldingfeedstock and a silicon-containing compound or silicon-containingcompound alone.

It is preferred that the first feedstock comprises a carbonblack-yielding feedstock and that at least about 5% by weight of thetotal amount of carbon black-yielding feedstock used in the process ispresent in the first feedstock. More preferably, from about 10% byweight to about 100% by weight, and even more preferably, from about 40%by weight to about 100% by weight of the total amount of carbonblack-yielding feedstock used in said method is present in the firstfeedstock.

In another embodiment of the present invention, the aggregate orsilicon-treated carbon black of the present invention can be made usinga multi-stage reactor, wherein the reactor has at least three stages forintroducing feedstocks into the reactor. The second and third stages, aswell as any additional stages, are located downstream of the firststage. As stated earlier, these stages can be located anywheredownstream as long as there is a sufficient temperature and residencetime for the silicon-treated carbon black to form before any quenchingoccurs. Each of the feedstocks introduced into the stages comprises acarbon black-yielding feedstock, a silicon-containing compound, or amixture thereof. At least one of the stages comprises a carbonblack-yielding feedstock and at least one of the stages, which can bethe same stage containing the carbon black-yielding feedstock, comprisesa silicon-containing compound. The reactor is maintained at a sufficienttemperature to decompose the silicon-containing compound and to pyrolizethe carbon black-yielding feedstock.

Referring to the FIGURE again, the mixture of feedstocks and hotcombustion gases flows downstream through zones 3 and 4. In the reactionzone portion of the reactor, the portion of the feedstock which containsthe carbon black-yielding feedstock is pyrolyzed to carbon black to formthe carbon phase of the aggregate. The feedstock portion containing thesilicon-containing compound undergoes volatilization and decomposes, andpreferably reacts with other species in the reaction zone and forms asilicon-containing species phase. The presence of the carbonblack-yielding feedstock and the silicon-containing compound in thereactor leads to the aggregate comprising a carbon phase and asilicon-containing species phase. The silicon-containing species are anintrinsic part of the aggregate and are part of the same aggregate asthe carbon phase. An example of a silicon-containing species is silica.Besides volatilizable compounds, decomposable compounds which are notnecessarily volatilizable can also be used to yield thesilicon-containing species phase of the aggregates of the presentinvention. As stated earlier, besides the formation of an aggregatecomprising a carbon phase and a silicon-treated species phase, carbonblack and/or silica may additionally be formed.

The reaction in the reaction zone is then arrested in the quench zone ofthe reactor. Quench 8 is located downstream of the feedstock entrypoints and the reaction zone and sprays a quenching fluid, generallywater, into the stream of newly formed aggregates or silicon-treatedcarbon black and any carbon black and/or silica that may also bepresent. The quench serves to cool the aggregates or particles and toreduce the temperature of the gaseous stream and decrease the reactionrate. Q is the distance from the beginning reaction zone 4 to quench 8and will vary according to the position of the quench. Optionally,quenching may be staged, or take place at several points in the reactor.

After the aggregates or particles are quenched, the cooled gases and theaggregates pass downstream into any conventional cooling and separatingmeans whereby the aggregates and any coproduced carbon black and/orsilica are recovered. The separation of the aggregates from the gasstream is readily accomplished by conventional means such as aprecipitator, cyclone separator, bag filter, or other means known tothose skilled in the art. After the aggregates have been separated fromthe gas stream, they are optionally subjected to a pelletization step.

Useful volatilizable silicon-containing compounds include any suchcompound which is volatilizable at carbon black reactor temperatures.Examples include, but are not limited to, silicates such astetraethoxyorthosilicate (TEOS) and tetramethoxyorthosilicate, silanesfor example alkoxysilanes, algylalkoxysilanes andaryl-alkylalkoxysilanes, for example, tetramethoxysilane,tetraethoxysilane, methyltrimethoxy-silane, methyltriethoxy silane,dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane,trimethylethoxysilane, diethylpropylethoxysilane, halogen-organosilanesfor examples, tetrachiorosilane, trichloromethylsilane,dimethyl-dichlorosilane, trimethylchlorosilane,methyethyldichlorosilane, dimethylethylchlorosilane,dimethyethylbromosilane, silicone oil, polysiloxanes and cyclicpolysiloxanes for example, octamethylcyclotetrasiloxane (OMTS),decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane,hexamethyl-cyclotrisiloxane, and silazanes for example,hexamethyldisilazane. Besides volatilizable compounds. decomposablesilicon-containing compounds which are not necessarily volatilizable canalso be used to yield the silicon-treated carbon black.Silicon-containing compounds which may be used are set forth inEncyclopedia of Science and Engineering, Vol. 15, 2nd Ed pp. 204-308,and UK Patent Application 2 296 915, both incorporated herein byreference. The usefulness of these compounds can be readily determinedfor their volatilizability and/or decomposability. Low molecular weightsilicon-containing compounds are preferred. The flow rate of thevolatilizable compound will determine the weight percent of silicon inthe silicon-treated carbon black.

Generally, if the silicon-containing compound is introducedsubstantially simultaneously with the carbon black-yielding feedstock,the silicon-containing species phase(s) are distributed throughout theaggregate. If the silicon-containing compound is introduced to thereaction zone at a point after the carbon black formation has commenced(i.e., during the formation of the carbon phase), but before thereaction stream has been subjected to the quench, the silicon-containingspecies phase is present primarily at or near the surface of theaggregate but is still part of the same aggregate as the carbon phase.

In general, the multi-phase aggregates of the present invention can beused either in nonagglomerated form, i.e., fluffy, or in agglomeratedform. The multi-phase aggregate can be agglomerated in wet or dryprocesses as known in the art. During the wet agglomeration process,different types of pelletizing agents (e.g., binders and the like) canbe added to the pelletizing water, see e.g. WO96/29710, incorporatedherein by reference. Also, a coupling agent may be attached to theaggregate before or after pelletization, as described in U.S. patentapplication Ser. No. 08/850,145, incorporated in its entirety herein byreference.

The aggregate of the present invention can be characterized by one ormore of the following various properties. For instance, the aggregatecan have a rough surface characterized by the difference between BET(N₂) surface area and t-area which preferably ranges from about 2 toabout 100 m²/g. For an aggregate with t-area above 100 m²/g, thedifference between BET (N₂) surface area and t-area is preferably fromabout 10 to about 50 m²/g. The surface roughness of HF treated aggregateis characterized by the difference between BET (N₂) surface area andt-area, which generally ranges from about 1 to about 50 m²/g, and morepreferably from about 5 to about 40 m²/g. After HF treatment, theaggregate still has a rough surface. The surface roughness of the HFtreated aggregate is characterized by the ratio of the difference in BET(N₂) surface area between the aggregate after and before HF treatment tothe silicon content (in weight percentage) of the original aggregatesample without HF treatment. This ratio is preferably from about 0.1 toabout 10 and more preferably from about 0.5 to about 5. The weightaverage aggregate size measured by DCP after HF treatment is reducedgenerally by about 5% to about 40% compared to an untreated aggregate. Asignificant amount of silica can remain in the aggregate after HFtreatment. The remaining silica ash content preferably ranges from about0.05% to about 1 % based on the weight of the HF treated sample. Thisamount of silica ash in the aggregate comprises silica ash orginatingfrom the silicon-containing compound, and not from any carbonblack-yielding feedstock. The BET surface area of the silica ash in theaggregate made after thermal treatment in air at 500° C. generallyranges from about 200 m²/g to about 1000 m²/g, and preferably rangesfrom about 200 m²/g to about 700 m²/g. As stated earlier, anycombination is possible for the various properties and the aggregate canhave one, any two, any three, any four, any five, or all of theproperties. Additionally, all of these aggregates can generally containsulfur and/or nitrogen levels between about 0.1 and about 5 wt %, basedon the weight of the aggregate.

The weight percent of silicon in the silicon-treated carbon blackpreferably ranges from about 0.1% to about 25%, and more preferably fromabout 0.5% to about 10%, and most preferably from about 4% to about 10%by weight or from about 8% to about 15% by weight of the aggregate. Froman economical point of view, the use of less silicon is preferable tothe extent that it reduces the cost to make the aggregate, providedacceptable performance characteristics are achieved. It has been foundthat injecting a silicon-containing compound into the carbon blackreactor can result in an increase in the structure (e.g., CDBP) of theproduct.

It is preferred that a diluent is also present in any feedstockincluding the silicon-containing compound. The diluent should bevolatilizable and/or decomposable since it will be preferably injectedinto the reactor along with the silicon-containing compound. The diluentcan as well also serve as a carbon black-yielding feedstock. Forinstance, the diluent can comprise alcohol or mixtures thereof which canserve as the carbon black-yielding feedstock as well as the diluent. Thediluent is preferably capable of increasing the mass flow rate of thefeedstock in which it is contained and/or is capable of lowering thetemperature of the reactor at about the point of introduction of thefeedstock which contains the diluent. The lower temperature assists incausing the silica domain aggregate to be finer and more numerous. Thediluent can comprise a liquid and/or a gas and is preferably misciblewith the silicon-containing compounds though this is not necessary.Further examples of diluents are water and aqueous based solutions. Thediluent can be present in any amount and is preferably present inamounts which will increase the mass flow rate of the feedstock and/orlower the temperature of the reactor at about the point of introductionof the feedstock. The diluent can also be included in feedstocks whichdo not contain any silicon-containing compound, or can be introduced ina separate stage.

In a further embodiment of the present invention, an aggregatecomprising a carbon phase and a metal-containing species phase can bemade also using a multi-stage reactor, wherein the reactor has at leasttwo stages for introducing the feedstocks into the reactor. The second,as well as any additional stages, are located downstream of the firststage. Each of the feedstocks introduced into the stages comprise acarbon black-yielding feedstock, a metal-containing compound, or amixture thereof. At least one of the feedstocks comprises a carbonblack-yielding feedstock and at least one of the feedstocks, which canbe the same stage containing the carbon black-yielding feedstock,comprises a metal-containing compound. In addition, any one of thefeedstocks further comprise a silicon-containing compound and/orboron-containing compound. The reactor is maintained at a temperaturesufficient to decompose the metal-containing compound and to form acarbon phase (i.e., pyrolize the carbon black-yielding feedstock). Ifany silicon-containing compound or boron-containing compound isadditionally present, the reactor should be also maintained at atemperature sufficient to decompose the silicon- containing compound orboron-containing compound. The aggregate formed by this process can bealso considered a metal-treated carbon black or a metal-treated carbonblack aggregate.

The metal-treated carbon black includes one metal-containing regionconcentrated at or near the surface of the aggregate (but stillconstituting part of the aggregate) or within the aggregate. Themetal-treated carbon black thus comprises two phases, one of which iscarbon and the other of which is a metal-containing species. Themetal-containing species phase included in the aggregate is not attachedto a carbon black aggregate like a silica coupling agent, or coated onto a pre-formed aggregate but actually is part of the same aggregate asthe carbon phase. Further, it is within the bounds of the presentinvention to use more than one type of metal-containing compound in thefeedstocks. If more than one type of metal-containing compound is usedin the feedstocks, then an aggregate comprising a carbon phase and twoor more different metal-containing species phases would be formed. Inaddition, if a silicon-containing compound is included in one of thefeedstocks, then a silicon-containing species phase would also be formedas part of the same aggregate containing the carbon phase and themetal-containing species phase(s). In addition, a boron-containingcompound can also be included in the feedstocks, and if present, wouldform a boron-containing species phase as part of the same aggregatecontaining the carbon phase and the metal-containing species phase.Accordingly, the metal-treated carbon black formed from the process ofthe present invention can have two or more different types ofmetal-containing species phases and/or additional non-metal speciesphases. The process used to make the aggregate comprising a carbon phaseand a silicon-containing species phase can be substantially used to makethe aggregate comprising a carbon phase and a metal-containing speciesphase.

Besides producing an aggregate comprising a carbon phase and ametal-containing species phase, carbon black and/or metal oxides mayalso result from the process of the present invention. One couldconsider the optional formation of one or more metal oxides and/orcarbon black as co-products of the process which would also be presentalong with the aggregate comprising a carbon phase and ametal-containing species phase and would provide additional benefitswhen incorporated into elastomeric compositions.

The metal-containing species include compounds containing aluminum,zinc, magnesium, calcium, titanium, vanadium, cobalt, nickel, zirconium,tin, antimony, chromium, neodymium, lead, tellurium, barium, cesium,iron, and molybdenum. Preferably, the metal-containing species phase isan aluminum- or zinc-containing species phase. The metal-containingspecies include, but are not limited to, oxides of metals.

Useful volatilizable compounds (i.e., the metal-containing compounds)include any compound which is volatilizable at carbon black reactortemperatures. Examples include volatilizable or decomposable compoundscontaining aluminum, zinc, magnesium, calcium, titanium, vanadium,cobalt, nickel, zirconium, tin, antimony, chromium, neodymium, lead,tellurium, barium, cesium, iron, and molybdenum. Specific examplesinclude, but are not limited to, butoxides such as Aluminum IIIn-Butoxide and Aluminum III s-Butoxide, and propoxides, such as Al IIIiso-propoxide. Examples of suitable zinc-containing compounds include,but are not limited to, zinc napthenate and zinc octoate. Other examplesinclude, but are not limited to, magnesium ethoxide, magnesiumisopropoxide, calcium propoxide, titanium isopropoxide, cobaltousnapthenate, tin diethyl oxide, neodymium oxalate, and the like. The flowrate of the volatilizable compound will determine the weight percent ofmetal in the treated carbon black. The weight percent of the elementalmetal (e.g., elemental aluminum or zinc) in the metal-treated carbonblack generally ranges from about 0. 1% to 25%, by weight of theaggregate, by may be adjusted to any desired level, such as up to 50% byweight, greater than 50% by weight, or up to 99% by weight of theaggregate.

Besides volatilizable compounds, decomposable metal-containing compoundswhich are not necessarily volatilizable can also be used to yield themetal-treated carbon black.

The aggregates made in accordance with the process of the presentinvention can be incorporated into elastomeric compounds which may beadditionally compounded with one or more coupling agents to furtherenhance the properties of the elastomeric compound.

Coupling agents, as used herein, include, but are not limited to,compounds that are capable of coupling fillers such as carbon black orsilica to an elastomer. Coupling agents useful for coupling silica orcarbon black to an elastomer, are expected to be useful with thesilicon-treated carbon blacks. Useful coupling agents include, but arenot limited to, silane coupling agents such asbis(3-triethoxysilylpropyl)tetrasulfane (Si-69),3-thiocyanatopropyl-triethoxy silane (Si-264, from Degussa AG, Germany),γ-mercaptopropyl-trimethoxy silane (A189, from Union Carbide Corp.,Danbury, Conn.); zirconate coupling agents, such as zirconiumdineoalkanolatodi(3-mercapto) propionato-O (NZ 66A, from KenrichPetrochemicals, Inc., of Bayonne, New Jersey); titanate couplingagents;. nitro coupling agents such asN,N′-bis(2-methyl-2-nitropropyl)-1,6-diaminohexane (Sumifine 1162, fromSumitomo Chemical Co., Japan); polyalkoxysiloxane (e.g. Zeruma from theYokohama Rubber Co. Ltd., Japan) and mixtures of any of the foregoing.The coupling agents may be provided as a mixture with a suitablecarrier, for example X50-S which is a mixture of Si-69 and N330 carbonblack, available from Degussa AG.

The silicon-treated carbon black incorporated in the elastomericcompound of the present invention may be oxidized and/or combined with acoupling agent. Suitable oxidizing agents include, but are not limitedto, nitric acid and ozone. Coupling agents which may be used with theoxidized carbon blacks include, but are not limited to, any of thecoupling agents set forth above.

Further, the silicon-treated carbon blacks and/or metal-treated carbonblacks of the present invention may have an organic group attached.

One process for attaching an organic group to an aggregate involves thereaction of at least one diazonium salt with an aggregate in the absenceof an externally applied current sufficient to reduce the diazoniumsalt. That is, the reaction between the diazonium salt and the aggregateproceeds without an external source of electrons sufficient to reducethe diazonium salt. Mixtures of different diazonium salts may be used inthe process of the invention. This process can be carried out under avariety of reaction conditions and in any type of reaction medium,including both protic and aprotic solvent systems or slurries.

In another process, at least one diazoniium salt reacts with anaggregate in a protic reaction medium. Mixtures of different diazoniumsalts may be used in this process of the invention. This process canalso be carried out under a variety of reaction conditions.

Preferably, in both processes, the diazonium salt is formed in situ. Ifdesired, in either process, the carbon black product can be isolated anddried by means known in the art. Furthermore, the resultant carbon blackproduct can be treated to remove impurities by known techniques. Thevarious preferred embodiments of these processes are discussed below.

These processes can be carried out under a wide variety of conditionsand in general are not limited by any particular condition. The reactionconditions must be such that the particular diazonium salt issufficiently stable to allow it to react with the silicon-treated carbonblack. Thus, the processes can be carried out under reaction conditionswhere the diazonium salt is short lived. The reaction between thediazonium salt and the silicon-treated carbon black occurs, for example,over a wide range of pH and temperature. The processes can be carriedout at acidic, neutral, and basic pH. Preferably, the pH ranges fromabout 1 to 9. The reaction temperature may preferably range from 0° C.to 100° C.

Diazonium salts, as known in the art, may be formed for example by thereaction of primary amines with aqueous solutions of nitrous acid. Ageneral discussion of diazonium salts and methods for their preparationis found in Morrison and Boyd, Organic Chemistry, 5th Ed., pp. 973-983,(Allyn and Bacon, Inc. 1987) and March, Advanced Organic Chemistry:Reactions, Mechanisms, and Structures, 4th Ed., (Wiley, 1992). Accordingto this invention, a diazonium salt is an organic compound having one ormore diazonium groups.

The diazonium salt may be prepared prior to reaction with thesilicon-treated carbon black or, more preferably, generated in situusing techniques known in the art. In situ generation also allows theuse of unstable diazonium salts such as alkyl diazonium salts and avoidsunnecessary handling or manipulation of the diazonium salt. Inparticularly preferred processes, both the nitrous acid and thediazonium salt are generated in situ.

A diazonium salt, as is known in the art, may be generated by reacting aprimary amine, a nitrite and an acid. The nitrite may be any metalnitrite, preferably lithium nitrite, sodium nitrite, potassium nitrite,or zinc nitrite, or any organic nitrite such as for exampleisoamylnitrite or ethylnitrite. The acid may be any acid, inorganic ororganic, which is effective in the generation of the diazonium salt.Preferred acids include nitric acid, HNO₃, hydrochloric acid, HCl, andsulfuric acid, H₂SO₄.

The diazonium salt may also be generated by reacting the primary aminewith an aqueous solution of nitrogen dioxide. The aqueous solution ofnitrogen dioxide, NO₂/H₂O, provides the nitrous acid needed to generatethe diazonium salt.

Generating the diazonium salt in the presence of excess HCl may be lesspreferred than other alternatives because HCl is corrosive to stainlesssteel. Generation of the diazonium salt with NO₂/H₂O has the additionaladvantage of being less corrosive to stainless steel or other metalscommonly used for reaction vessels. Generation using H₂SO₄/NaNO₂ orHNO₃/NaNO₂ are also relatively non-corrosive.

In general, generating a diazonium salt from a primary amine, a nitrite,and an acid requires two equivalents of acid based on the amount ofamine used. In an in situ process, the diazonium salt can be generatedusing one equivalent of the acid. When the primary amine contains astrong acid group, adding a separate acid may not be necessary. The acidgroup or groups of the primary amine can supply one or both of theneeded equivalents of acid. When the primary amine contains a strongacid group, preferably either no additional acid or up to one equivalentof additional acid is added to a process of the invention to generatethe diazonium salt in situ. A slight excess of additional acid may beused. One example of such a primary amine is para-aminobenzenesulfonicacid (sulfanilic acid).

In general, diazonium salts are thermally unstable. They are typicallyprepared in solution at low temperatures, such as O-50° C., and usedwithout isolation of the salt. Heating solutions of some diazonium saltsmay liberate nitrogen and form either the corresponding alcohols inacidic media or the organic free radicals in basic media.

However, the diazonium salt need only be sufficiently stable to allowreaction with the silicon-treated carbon black. Thus, the processes canbe carried out with some diazonium salts otherwise considered to beunstable and subject to decomposition. Some decomposition processes maycompete with the reaction between the silicon-treated carbon black andthe diazonium salt and may reduce the total number of organic groupsattached to the silicon-treated carbon black. Further, the reaction maybe carried out at elevated temperatures where many diazonium salts maybe susceptible to decomposition. Elevated temperatures may alsoadvantageously increase the solubility of the diazonium salt in thereaction medium and improve its handling during the process. However,elevated temperatures may result in some loss of the diazonium salt dueto other decomposition processes.

Reagents can be added to form the diazonium salt in situ, to asuspension of silicon-treated carbon black in the reaction medium, forexample, water. Thus, a carbon black suspension to be used may alreadycontain one or more reagents to generate the diazonium salt and theprocess accomplished by adding the remaining reagents.

Reactions to form a diazonium salt are compatible with a large varietyof functional groups commonly found on organic compounds. Thus, only theavailability of a diazonium salt for reaction with a silicon-treatedcarbon black limits the processes of the invention.

The processes can be carried out in any reaction medium which allows thereaction between the diazonium salt and the silicon-treated carbon blackto proceed. Preferably, the reaction medium is a solvent-based system.The solvent may be a protic solvent, an aprotic solvent, or a mixture ofsolvents. Protic solvents are solvents, like water or methanol,containing a hydrogen attached to an oxygen or nitrogen and thus aresufficiently acidic to form hydrogen bonds. Aprotic solvents aresolvents which do not contain an acidic hydrogen as defined above.Aprotic solvents include, for example, solvents such as hexanes,tetrahydrofuran (THF), acetonitrile, and benzonitrile. For a discussionof protic and aprotic solvents see Morrison and Boyd, Organic Chemistry,5th Ed., pp. 228-231, (Allyn and Bacon, Inc. 1987).

The processes are preferably carried out in a protic reaction medium,that is, in a protic solvent alone or a mixture of solvents whichcontains at least one protic solvent. Preferred protic media include,but are not limited to water, aqueous media containing water and othersolvents, alcohols, and any media containing an alcohol, or mixtures ofsuch media.

The reaction between a diazonium salt and a silicon-treated carbon blackcan take place with any type of silicon-treated carbon black, forexample, in fluffy or pelleted form. In one embodiment designed toreduce production costs, the reaction occurs during a process forforming silicon-treated carbon black pellets. For example, asilicon-treated carbon black product of the invention can be prepared ina dry drum by spraying a solution or slurry of a diazonium salt onto asilicon-treated carbon black. Alternatively, the silicon-treated carbonblack product can be prepared by pelletizing a silicon-treated carbonblack in the presence of a solvent system, such as water, containing thediazonium salt or the reagents to generate the diazonium salt in situ.Aqueous solvent systems are preferred. Accordingly, another embodimentprovides a process for forming a pelletized silicon-treated carbon blackcomprising the steps of: introducing a silicon-treated carbon black andan aqueous slurry or solution of a diazonium salt into a pelletizer,reacting the diazonium salt with the silicon-treated carbon black toattach an organic group to the silicon-treated carbon black, andpelletizing the resulting silicon-treated carbon black having anattached organic group. The pelletized silicon-treated carbon blackproduct may then be dried using conventional techniques.

In general, the processes produce inorganic by-products, such as salts.In some end uses, such as those discussed below, these by-products maybe undesirable. Several possible ways to produce a silicon-treatedcarbon black product without unwanted inorganic by-products or salts areas follows:

First, the diazonium salt can be purified before use by removing theunwanted inorganic by-product using means known in the art. Second, thediazonium salt can be generated with the use of an organic nitrite asthe diazotization agent yielding the corresponding alcohol rather thanan inorganic salt. Third, when the diazonium salt is generated from anamine having an acid group and aqueous NO₂, no inorganic salts areformed. Other ways may be known to those of skill in the art.

In addition to the inorganic by-products, a process may also produceorganic by-products. They can be removed, for example, by extractionwith organic solvents. Other ways of obtaining products without unwantedorganic by-products may be known to those of skill in the art andinclude washing or removal of ions by reverse osmosis.

The reaction between a diazonium salt and a silicon-treated carbon blackforms a silicon-treated carbon black product having an organic groupattached to the silicon-treated carbon black. The diazonium salt maycontain the organic group to be attached to the silicon-treated carbonblack. It may be possible to produce the silicon-treated carbon blackproducts of this invention by other means known to those skilled in theart.

The organic group may be an aliphatic group, a cyclic organic group, oran organic compound having an aliphatic portion and a cyclic portion. Asdiscussed above, the diazonium salt employed in the processes can bederived from a primary amine having one of these groups and beingcapable of forming, even transiently, a diazonium salt. The organicgroup may be substituted or unsubstituted, branched or unbranched.Aliphatic groups include, for example, groups derived from alkanes,alkenes, alcohols, ethers, aldehydes, ketones, carboxylic acids, andcarbohydrates. Cyclic organic groups include, but are not limited to,alicyclic hydrocarbon groups (for example, cycloalkyls, cycloalkenyls),heterocyclic hydrocarbon groups (for example, pyrrolidinyl, pyrrolinyl,piperidinyl, morpholinyl, and the like), aryl groups (for example,phenyl, naphthyl, anthracenyl, and the like), and heteroaryl groups(imidazolyl, pyrazolyl, pyridinyl, thienyl, thiazolyl, furyl, indolyl,and the like). As the steric hinderance of a substituted organic groupincreases, the number of organic groups attached to the silicon-treatedcarbon black from the reaction between the diazonium salt and thesilicon-treated carbon black may be diminished.

When the organic group is substituted, it may contain any functionalgroup compatible with the formation of a diazonium salt. Preferredfunctional groups include, but are not limited to, R, OR, COR, COOR,OCOR, carboxylate salts such as COOLi, COONa, COOK, COO⁻NR₄ ⁺, halogen,CN, NR₂, SO₃H, sulfonate salts such as SO₃Li, SO₃Na, SO₃K, SO₃ ⁻NR₄ ⁺,OSO₃H, OSO₃ ⁻ salts, NR(COR), CONR₂, NO₂, PO₃H₂, phosphonate salts suchas PO₃HNa and PO₃Na₂, phosphate salts such as OPO₃HNa and OPO₃Na₂, N=NR,NR₃ ⁺X⁻, PR₃ ⁺X⁻, S_(k)R, SSO₃H, SSO₃ ⁻ salts, SO₂NRR′, SO₂SR, SNRR′,SNQ, SO₂NQ, CO₂NQ, S-(1,4-piperazinediyl)-SR, 2-(1,3-dithianyl)2-(1,3-dithiolanyl), SOR, and SO₂R. R and R′, which can be the same ordifferent, are independently hydrogen, branched or unbranched C₁-C₂₀substituted or unsubstituted, saturated or unsaturated hydrocarbon,e.g., alkyl, alkenyl, alkynyl, substituted or unsubstituted aryl,substituted or unsubstituted heteroaryl, substituted or unsubstitutedalkylaryl, or substituted or unsubstituted arylalkyl. The integer kranges from 1-8 and preferably from 2-4. The anion X⁻ is a halide or ananion derived from a mineral or organic acid. Q is (CH₂)_(w),(CH₂)_(x)O(CH₂)_(z), (CH₂)_(x)NR(CH₂)_(z), or (CH₂)_(x)S(CH₂)_(z), wherew is an integer from 2 to 6 and x and z are integers from 1 to 6.

A preferred organic group is an aromatic group of the formula A_(y)Ar—,which corresponds to a primary amine of the formula A_(y)ArNH₂. In thisformula, the variables have the following meanings: Ar is an aromaticradical such as an aryl or heteroaryl group. Preferably, Ar is selectedfrom the group consisting of phenyl, naphthyl, anthracenyl,phenanthrenyl, biphenyl, pyridinyl, benzothiadiazolyl, andbenzothiazolyl; A is a substituent on the aromatic radical independentlyselected from a preferred functional group described above or A is alinear, branched or cyclic hydrocarbon radical (preferably containing 1to 20 carbon atoms), unsubstituted or substituted with one or more ofthose functional groups; and y is an integer from 1 to the total numberof —CH radicals in the aromatic radical. For instance, y is an integerfrom 1 to 5 when Ar is phenyl, 1 to 7 when Ar is naphthyl, 1 to 9 whenAr is anthracenyl, phenanthrenyl, or biphenyl, or 1 to 4 when Ar ispyridinyl. In the above formula, specific examples of R and R′ areNH₂—C₆H₄—, CH₂CH₂—C₆H₄—NH₂, CH₂—C₆H₄—NH₂, and C₆H₅.

Another preferred set of organic groups which may be attached to thesilicon-treated carbon black are organic groups substituted with anionic or an ionizable group as a functional group. An ionizable group isone which is capable of forming an ionic group in the medium of use. Theionic group may be an anionic group or a cationic group and theionizable group may form an anion or a cation.

Ionizable functional groups forming anions include, for example, acidicgroups or salts of acidic groups. The organic groups, therefore, includegroups derived from organic acids. Preferably, when it contains anionizable group forming an anion, such an organic group has a) anaromatic group and b) at least one acidic group having a pKa of lessthan 11, or at least one salt of an acidic group having a pKa of lessthan 11, or a mixture of at least one acidic group having a pKa of lessthan 11 and at least one salt of an acidic group having a pKa of lessthan 11. The pKa of the acidic group refers to the pKa of the organicgroup as a whole, not just the acidic substituent. More preferably, thepKa is less than 10 and most preferably less than 9. Preferably, thearomatic group of the organic group is directly attached to thesilicon-treated carbon black. The aromatic group may be furthersubstituted or unsubstituted, for example, with alkyl groups. Morepreferably, the organic group is a phenyl or a naphthyl group and theacidic group is a sulfonic acid group, a sulfinic acid group, aphosphonic acid group, or a carboxylic acid group. Examples of theseacidic groups and their salts are discussed above. Most preferably, theorganic group is a substituted or unsubstituted sulfophenyl group or asalt thereof; a substituted or unsubstituted (polysulfo)phenyl group ora salt thereof; a substituted or unsubstituted sulfonaphthyl group or asalt thereof; or a substituted or unsubstituted (polysulfo)naphthylgroup or a salt thereof. A preferred substituted sulfophenyl group ishydroxysulfophenyl group or a salt thereof.

Specific organic groups having an ionizable functional group forming ananion (and their corresponding primary amines) are p-sulfophenyl(p-sulfanilic acid), 4-hydroxy-3-sulfophenyl(2-hydroxy-5-amino-benzenesulfonic acid), and 2-sulfoethyl(2-aminoethanesulfonic acid). Other organic groups having ionizablefunctional groups forming anions can also be used.

Amines represent examples of ionizable functional groups that formcationic groups. For example, amines may be protonated to form ammoniumgroups in acidic media. Preferably, an organic group having an aminesubstituent has a pKb of less than 5. Quaternary ammonium groups (—NR₃⁺) and quaternary phosphonium groups (—PR₃ ⁺) also represent examples ofcationic groups. Preferably, the organic group contains an aromaticgroup such as a phenyl or a naphthyl group and a quaternary ammonium ora quaternary phosphonium group. The aromatic group is preferablydirectly attached to the carbon black. Quaternized cyclic amines, andeven quaternized aromatic amines, can also be used as the organic group.Thus, N-substituted pyridinium compounds, such as N-methyl-pyridyl, canbe used in this regard. Examples of organic groups include, but are notlimited to, (C₅H₄N)C₂H₅ ⁺, C₆H₄(NC₅H₅)⁺, C₆H₄COCH₂N(CH₃)₃ ⁺,C₆H₄COCH₂(NC₅H₅)⁺, (C₅H₄N)CH₃ ⁺, and C₆H₄CH₂N(CH₃)₃ ⁺.

An advantage of the silicon-treated carbon black products having anattached organic group substituted with an ionic or an ionizable groupis that the silicon-treated carbon black product may have increasedwater dispersibility relative to the corresponding untreated carbonblack. Water dispersibility of a silicon-treated carbon black productincreases with the number of organic groups attached to thesilicon-treated carbon black having an ionizable group or the number ofionizable groups attached to a given organic group. Thus, increasing thenumber of ionizable groups associated with the silicon-treated carbonblack product should increase its water dispersibility and permitscontrol of the water dispersibility to a desired level. It can be notedthat the water dispersibility of a silicon-treated carbon black productcontaining an amine as the organic group attached to the silicon-treatedcarbon black may be increased by acidifying the aqueous medium.

Because the water dispersibility of the silicon-treated carbon blackproducts depends to some extent on charge stabilization, it ispreferable that the ionic strength of the aqueous medium be less than0.1 molar. More preferably, the ionic strength is less than 0.01 molar.

When such a water dispersible silicon-treated carbon black product isprepared, it is preferred that the ionic or ionizable groups be ionizedin the reaction medium. The resulting product solution or slurry may beused as is or diluted prior to use. Alternatively, the silicon-treatedcarbon black product may be dried by techniques used for conventionalcarbon blacks. These techniques include, but are not limited to, dryingin ovens and rotary kilns. Overdrying, however, may cause a loss in thedegree of water dispersibility.

In addition to their water dispersibility, silicon-treated carbon blackproducts having an organic group substituted with an ionic or anionizable group may also be dispersible in polar organic solvents suchas dimethylsulfoxide (DMSO), and formamide. In alcohols such as methanolor ethanol, use of complexing agents such as crown ethers increases thedispersibility of silicon-treated carbon black products having anorganic group containing a metal salt of an acidic group.

Aromatic sulfides encompass another group of preferred organic groups.Silicon-treated carbon black products having aromatic sulfide groups areparticularly useful in rubber compositions. These aromatic sulfides canbe represented by the formulas Ar(CH₂)_(q)S_(k)(CH₂)_(r)Ar′ orA-(CH₂)_(q)S_(K)(CH₂)_(r)Ar″ wherein Ar and Ar′ are independentlysubstituted or unsubstituted arylene or heteroarylene groups, Ar″ is anaryl or heteroaryl group, k is 1 to 8 and q and r are 0-4. Substitutedaryl groups would include substituted alkylaryl groups. Preferredarylene groups include phenylene groups, particularly p-phenylenegroups, or benzothiazolylene groups. Preferred aryl groups includephenyl, naphthyl and benzothiazolyl. The number of sulfurs present,defined by k preferably ranges from 2 to 4. Preferred silicon-treatedcarbon black products are those having an attached aromatic sulfideorganic group of the formula —(C₆H₄)—S_(k)—(C₆H₄)—, where k is aninteger from 1 to 8, and more preferably where k ranges from 2 to 4.Particularly preferred aromatic sulfide groups arebis-para-(C₆H₄)—S₂—(C₆H₄)— and para-(C₆H₄)—S₂—(C₆H₅). The diazoniumsalts of these aromatic sulfide groups may be conveniently prepared fromtheir corresponding primary amines, H₂N—Ar—S_(k)—Ar′—NH₂ orH₂N—Ar—S_(k)—Ar″. Preferred groups include dithiodi-4,1-phenylene,tetrathiodi-4,1-phenylene, phenyldithiophenylene,dithiodi-4,1-(3-chlorophenylene), —(4-C₆H₄)—S—S-(2-C₇H₄NS),-(4-C₆H₄)—S—S-(4-C₆H₄)—OH, -6-(2-C₇H₃NS)—SH,-(4-C₆H₄)—CH₂CH₂—S—S—CH₂-(4-C₆H₄)—,-(4-C₆H₄)—CH₂CH₂—S—S—S—CH₂CH₂-(4-C₆H₄)—, -(2-C₆H₄)—S-(2-C₆H₄)—,-(3-C₆H₄)—S—S-(3-C₆H₄)—, -6-(C₆H₃N₂S), -6-(2-C₇H₃NS)—S—NRR′ where RR′ isCH₂CH₂OCH₂CH₂—, -(4-C₆H₄)—S—S—S—S-(4-C₆H₄)—, -(4-C₆H₄)—CH═CH₂,-(4-C₆H₄)—S—SO₃H, -(4-C₆H₄)—SO₂NH-(4-C₆H₄)—S—S-(4-C₆H₄)—NHSO₂-(4-C₆H₄)—,-6-(2-C₇H₃NS)—S—S—2-(6-C₇H₃NS)—, -(4-C₆H₄)—S—CH₂-(4-C₆H₄)—,-(4-C₆H₄)—SO₂—S-(4-C₆H₄)—, -(4-C₆H₄)—CH₂—S—CH₂-(4-C₆H₄)—,-(3-C₆H₄)—CH₂—S—CH₂-(3-C₆H₄)—, -(4-C₆H₄)—CH₂—S—S—CH₂-(4-C₆H₄)—,-(3-C₆H₄)—, -(3-C₆H₄)—CH₂—S—S—CH₂-(3—C₆H₄)—,-(4-C₆H₄)—CH₂—S—S—CH₂-(4-C₆H₄)—, -(3-C₆H₄)—CH₂—CH₂—S—S—CH₂-(3-C₆H₄)—,-(4-C₆H₄)—S—NRR′ where RR′ is —CH₂CH₂OCH₂CH₂—,-(4-C₆H₄)—SO₂NH—CH₂CH₂—S—S—CH₂CH₂—NHSO₂-(4-C₆H₄)—,-(4-C₆H₄)-2-(1,3-dithianyl;), and-(4-C₆H₄)—S-(1,4-piperizinediyl)—S-(4-C₆H₄)—.

Another preferred set of organic groups which may be attached to thecarbon black are organic groups having an aminophenyl, such as(C₆H₄)—NH₂, (C₆H₄)—CH₂—(C₆H₄)—NH₂, (C₆H₄)—SO₂—(C₆H₄)—NH₂. Preferredorganic groups also include aromatic sulfides, represented by theformulas Ar—S_(n)—Ar′ or Ar—S_(n)—Ar″, wherein Ar and Ar′ areindependently arylene groups, Ar″ is an aryl and n is 1 to 8. Methodsfor attaching such organic groups to carbon black are discussed in U.S.Pat. Nos. 5,554,739 and 5,559,169; U.S. patent application Ser. Nos.08/356,660 and 08/572,525; and PCT Published Patent Application Nos. WO96/18688 and WO 96/18696, all of the disclosures of which are fullyincorporated by reference herein.

As stated earlier, the silicon-treated carbon black or metal-treatedcarbon black may also be modified to have at least one organic groupattached to the silicon-treated carbon black. Alternatively, a mixtureof silicon-treated carbon black and/or a metal-treated carbon black witha modified carbon black having at least one attached organic group maybe used.

Furthermore, it is within the bounds of this application to also use amixture of silica and silicon-treated carbon black and/or metal-treatedcarbon black. Also, any combination of additional components with thesilicon-treated carbon black or metal-treated carbon black may be usedsuch as one or more of the following:

a) silicon-treated carbon black with an attached organic groupoptionally treated with silane coupling agents;

b) modified carbon black having an attached organic group;

c) carbon black at least partially coated with silica;

d) silica;

e) modified silica, for example, having an attached coupling group,and/or

f) carbon black.

The term “silica” includes, but is not limited to, silica, precipitatedsilica, amorphous silica, vitreous silica, fumed silica, fused silica,silicates (e.g., alumino silicates) and other Si containing fillers suchas clay, talc, wollastonite, etc. Silicas are commercially availablefrom such sources as Cabot Corporation under the Cab-O-Sil® tradename;PPG Industries under the Hi-Sil and Ceptane tradenames; Rhone-Poulencunder the Zeosil tradename; and Degussa AG under the Ultrasil andCoupsil tradenames.

The elastomeric compounds of the present invention may be prepared fromthe silicon-treated carbon blacks and/or metal-treated carbon blacks bycompounding with any elastomer including those useful for compounding acarbon black.

Any suitable elastomer may be compounded with the silicon-treated carbonblacks and/or metal-treated carbon blacks to provide the elastomericcompounds of the present invention. Such elastomers include, but are notlimited to, homo- or co-polymers of 1,3 butadiene, styrene, isoprene,isobutylene, 2,3-dimethyl-1,3-butadiene, acrylonitrile, ethylene, andpropylene Preferably, the elastomer has a glass transition temperature(Tg) as measured by differential scanning colorimetry (DSC) ranging fromabout −120° C. to about 0° C. Examples include, but are not limited,styrene-butadiene rubber (SBR), natural rubber, polybutadiene,polyisoprene, and their oil-extended derivatives. Blends of any of theforegoing may also be used.

Among the rubbers suitable for use with the present invention arenatural rubber and its derivatives such as chlorinated rubber. Thesilicon-treated carbon black products or metal-treated carbon blackproducts of the invention may also be used with synthetic rubbers suchas: copolymers of from about 10 to about 70 percent by weight of styreneand from about 90 to about 30 percent by weight of butadiene such ascopolymer of 19 parts styrene and 81 parts butadiene, a copolymer of 30parts styrene and 70 parts butadiene, a copolymer of 43 parts styreneand 57 parts butadiene and a copolymer of 50 parts styrene and 50 partsbutadiene; polymers and copolymers of conjugated dienes such aspolybutadiene, polyisoprene, polychloroprene, and the like, andcopolymers of such conjugated dienes with- an ethylenic group-containingmonomer copolymerizable therewith such as styrene, methyl styrene,chlorostyrene, acrylonitrile, 2-vinyl-pyridine, 5-methyl2-vinylpyridine, 5-ethyl-2-vinylpyridine, 2-methyl-5-vinylpyridine,alkyl-substituted acrylates, vinyl ketone, methyl isopropenyl ketone,methyl vinyl either, alphamethylene carboxylic acids and the esters andamides thereof such as acrylic acid and dialkylacrylic acid amide; alsosuitable for use herein are copolymers of ethylene and other high alphaolefins such as propylene, butene-1 and pentene-1.

The rubber compositions of the present invention can therefore containan elastomer, curing agents, reinforcing filler, a coupling agent, and,optionally, various processing aids, oil extenders, and antidegradents.In addition to the examples mentioned above, the elastomer can be, butis not limited to, polymers (e.g., homopolymers, copolymers, andterpolymers) manufactured from 1,3 butadiene, styrene, isoprene,isobutylene, 2,3-dimethyl-1,3 butadiene, acrylonitrile, ethylene,propylene, and the like. It is preferred that these elastomers have aglass transition point (Tg), as measured by DSC, between −120° C. and 0°C. Examples of such elastomers include poly(butadiene),poly(styrene-co-butadiene), and poly(isoprene).

Elastomeric compositions disclosed in the present invention include, butare not limited to, vulcanized compositions (VR), thermoplasticvulcanizates (TPV), thermoplastic elastomers (TPE) and thermoplasticpolyolefins (TPO). TPV, TPE, and TPO materials are further classified bytheir ability to be extruded and molded several times without loss ofperformance characteristics.

The elastomeric compositions may include one or more curing agents suchas, for example, sulfur, sulfur donors, activators, accelerators,peroxides, and other systems used to effect vulcanization of theelastomer composition.

The resultant elastomeric compounds containing the aggregates of thepresent invention and optionally containing one or more coupling agentsmay be used for various elastomeric products such as a tread compound,undertread compound, sidewall compound, wire skim compound, innerlinercompound, bead, apex, any compound used in carcass and other componentsfor vehicle tires, industrial rubber products, seals, timing belts,power transmission belting, and other rubber goods.

The elastomeric compositions of the present invention preferably improverolling resistance and/or wet traction, especially for tire compoundscompared to the same elastomeric compositions without any aggregate ofthe present invention. Preferably, the increase for either property isat least 3%, more preferably at least 8%, and more preferably from about3% to about 20% compared to the same elastomeric composition containingcarbon black and not any aggregate of the present invention.

The present invention will be further clarified by the followingexamples, which are intended to be purely exemplary of the presentinvention.

EXAMPLES Example 1

Silicon-treated carbon blacks according to the present invention wereprepared using a pilot scale reactor generally as described above, andas depicted in the FIG. having the dimensions set forth below: D₁=7.25inches, D₂=4.5 inches, D₃=5.3 inches, D₄=13.5 inches, L₁=24 inches,L₂′=12 inches, L₂′=45 inches (for Example OMTS-CB-A′) and L₂=25 inches(for Examples OMTS-CB-B′, C′, D′, and E′) and Q=8.583 feet (for ExamplesOMTS-CB-A′, B′ and C′), Q=6.5 feet (for Examples OMTS-CB-D′ and E′). Thereaction conditions set forth in Table 1 below, were employed.

As shown in the FIGURE, a first feedstock was introduced at point 6 anda second feed stock was introduced at point 7. The first feedstockcontained a hydrocarbon (i.e. carbon black-yielding feedstock) and thesecond feedstock contained hydrocarbon and OMTS (i.e. asilicon-containing compound), namely octamethyl-cyclotetrasilioxane.This compound is sold as “D4” by Dow Corning Corporation, Midland, Mich.The resultant silicon-treated carbon black is identified herein asOMTS-CB.

Since changes in reactor temperature are known to alter the surface areaof the carbon black, and reactor temperature is very sensitive to thetotal flow rate of the feedstock in the injection zone (zone 3 in theFIGURE), the feedstock flow rate was adjusted downward to approximatelycompensate for the introduction of the volatilizable silicon-containingcompound. This results in an approximately constant external surfacearea (as measured by t area) for the resultant silicon-treated carbonblacks. All other conditions were maintained as necessary formanufacturing N234 carbon black. A structure control additive (potassiumacetate solution) was injected into the feedstock to maintain thespecification structure of the N234 carbon black. The flow rate of thisadditive was matintained constant in making the silicon-treated carbonblacks described throughout the following examples.

The BET (N₂) surface area was measured following the procedure describedin ASTM D4820-method B.

The external surface area (t-area) was measured following the samplespreparation and measurement procedure described in ASTM D5816. For thismeasurement, the nitrogen adsorption isotherm was extended up to 0.55relative pressure.

The relative pressure is the pressure (P) divided by the saturationpressure (P₀) (the pressure at which the nitrogen condenses). Theadsorption layer thickness (t₁) was then calculated using the relation:$t_{1} = \frac{13.99}{\sqrt{0.034\text{-}\log \quad \left( {P/P_{0}} \right)}}$

The volume (V) of nitrogen adsorbed was then plotted against t₁. Astraight line was then fitted through the data points for t, valuesbetween 3.9 and 6.2 Angstroms. The t-area was then obtained from theslope of this line as follows:

t-area, m²/gm=15.47×slope

The HF (hydrofluoric acid) treatment of the samples were carried outusing 5% v/v concentration of HF at boiling temperature for 1 h. Afterthe treatment, the samples were washed on a filter 20 times with waterand thereafter the washed aggregates were dried in preparation forfurther analysis.

The ash content of the aggregates was measured according to theprocedure described in ASTM D1506-method A.

The aggregate size of the filler was measured by means of DCP accordingto the method described in L. E. Oppenheimer, J. Colloid and InterfaceScience, 92, 350 (1983), incorporated herein by reference.

TABLE 1 CONDITIONS OMTS-CB- A′ B′ C′ D′ E′ Air Rate kscfh 60 60 60 60 60Gas Rate, kscfh 4.9 4.9 4.9 4.9 4.9 Feedstock Rate at 351 373 381 488284 point 6, lbs/hr Feedstock Rate at 287 305 312 163 418 point 7,lbs/hr OMTS rate at 22.2 50.2 50.2 46.6 46 point 7, lbs/hr

The analytical properties of the silicon-treated carbon black areprovided in Table 2. The various formulations and the mixing procedureused to produce the rubber compound using these silicon-treated carbonblacks are described in Tables 3 and 4. The performance of thesilicon-treated carbon blacks are described in Table 5. It is seen thatthe aggregates of the present invention made using the process describedabove result in a 6-10% improvement (compared to conventional carbonblack) in wet skid resistance as measured by the British Portable SkidTester.

The wet skid resistance (or wet traction) was measured by means of animproved British Portable Skid Tester (BPST) with the procedure reportedby Ouyang et al. (G. B. Ouyang, N. Tokita, and C. H. Shieh, “CarbonBlack Effects on Friction Properties of Tread Compound -Using a modifiedASTM-E303 Pendulum Skid Tester”, presented at a meeting of RubberDivision, ACS, Denver, Colo., May 18-21, 1993). The frictioncoefficients are referenced to carbon black N234-filled compound (100%).The higher the number, the higher (better) is the wet skid resistance.

TABLE 2 Analytical Properties of Carbon Blacks Si BET area t-area CDBPFiller % m²/g (N₂) m²/g mL/100 g N234 0.00 121.0 119.0 100.7 OMTS-CB-A′1.99 139.0 119.6 94.3 OMTS-CB-B′ 4.54 176.2 124.6 101.7 OMTS-CB-C′ 3.27176.2 123.8 100.6 OMTS-CB-D′ 4.40 171.4 124.1 99.1 OMTS-CB-E′ 4.40 168.5123.8 100.7

TABLE 3 Formulation N234 D4-CB SSBR (Duradene 715) 75 75 BR (Tacktene1203) 25 25 N234 75 — OMTS-CB — 75 Si 69 — 3 Oil (Sundex 8125) 25 25Zinc Oxide 3.5 3.5 Stearic Acid 2 2 Antioxident (Flexzone 7P) 1.5 1.5Wax (Sunproof Improved) 1.5 1.5 Durax 1.5 1.5 Vanax DPG — 1 TMTD 0.4 0.4Sulfur 1.4 1.4

Dudadene 715—solution SBR from Firestone Synthetic Rubber & Latex Co.,Akron, Ohio.

Tacktene 1203—Polybutadiene, from Bayer Fibres, Akron, Ohio.

Si 69—bis (3-triethoxysilylpropyl) tetrasulfide, from Degussa AG,Germany.

Sundex 8125—oil, from R.E.Carrol Inc., Trenton, N.J.

Zinc oxide—from New Jersey Zinc Co., New Zersey.

Stearic acid—from Emery Chemicals, Cincinnati, Ohio.

Flexon 7P—antioxidant, N-(1,3,-dimethyl butyl)—N′-phenyl-p-phenylenediamine, from Uniroyal Chemical Co. Middlebury, Conn.

Sunproof Improved—wax, from Uniroyal Chemical Co. Middlebury, Conn.

Durax—accelerator, N-cycloheane-2-benzothiazole sulphenamide, from R. T.Vanderbilt Co., Norwalk, Conn.

Vanax DPG—accelerator, diphenyl guanidine, from R. T. Vanderbilt Co.,Norwalk, Conn.

TMTD—accelerator, tetramethyl thiuram disulfide, from Uniroyal ChemicalCo. Middlebury, Conn.

Sulfur—from R.E.Carrol Inc., Trenton, N.J.

TABLE 4 Mixing Procedure for Tread Compounds of Passenger Tire Stage 1Brabender Plasti-corder EPL-V. 60 rpm, 80° C., air on, start all mixes @100° C. 0′ Add polymer 1′ Add filler, coupling agents (Preblended) @160°C. Add oil. 7′ @165° C. Dump. Pass through open mill 3 times. Sit atroom temperature for at least 2 hrs. Stage 2 60 rpm, 80° C., air on,start all mixes @ 100° C. 0′ Add masterbatch from stage 1. 1′ Add ZnO,Stearic acid. 3′ Add Flexzone 7P and Wax. 4′, @165° C. Dump Pass throughopen mill 3 times. Sit at room temperature for at least 2 hrs. Stage 335 rpm, 80° C. air on, start all mixes @ 100° C. 0′ Add masterbatch fromstage 2. 1′ Add curatives. 2′ Dump. Pass through open mill 3 times.

TABLE 5 Physical Properties of Vulcanizates Si 69 Wet skid Resistancetan δ Filler phr % 0° C. 70° C. N234 0.0 100 0.470 0.260 OMTS-CB-A′ 3.0110 0.414 0.195 OMTS-CB-B′ 3.0 110 0.387 0.162 OMTS-CB-C′ 3.0 108 0.3940.173 OMTS-CB-D′ 3.0 110 0.370 0.156 OMTS-CB-E′ 3.0 106 0.383 0.146

Example 2

Aggregates according to the present invention were prepared using apilot scale reactor generally as described above, and as depicted in theFIGURE having the dimensions set forth below:

D₁=7.25 inches, D₂=4.5 inches, D₃=5.3 inches, D₄=13.5 inches, L₁=24inches, L₂=12 inches, L₂′=29 inches, Q=6.5 feet. The reaction conditionsset forth in Table 1 below, were employed.

As shown in the FIGURE, a first feedstock was introduced at point 6 anda second feed stock was introduced at point 7. The first feedstockcontained a hydrocarbon (i.e. carbon black-yielding feedstock) and thesecond feedstock contained alcohol, namely iso-propanol and OMTS (i.e. asilicon-containing compound), namely octamethyl-cyclotetrasilioxane oroctamethyl-cyclotetrasilioxane alone. This compound is sold as “D4” byDow Corning Corporation, Midland, Mich. The resultant multiphaseaggregate is identified herein as MPCS 1-4.

Since changes in reactor temperature are known to alter the surface areaof the carbon black, and reactor temperature is very sensitive to thetotal flow rate of the feedstock in the injection zone (zone 3 in theFIG.), the feedstock flow rate was adjusted to approximately compensatefor the introduction of the volatilizable silicon-containing compound.This results in an approximately constant external surface area (asmeasured by t area) for the resultant silicon-treated carbon blacks. Allother conditions were maintained as necessary for manufacturing N234carbon black. A structure control additive (potassium acetate solution)was injected into the feedstock to maintain the specification structureof the N234 carbon black. The flow rate of this additive was maintainedconstant in making the multiphase aggregates described throughout thefollowing examples.

TABLE 6 CONDITIONS MPCS-1 MPCS-2 MPCS-3 MPCS-4 Air Rate nm³/h 1605 16061605 1607 Gas Rate nm³/h 132 133 134 133 Feedstock rate at 266 298 334346 point 6, kg/hr OMTS rate at 87.2 44 51 29.1 point 7, kg/hr Feedstock(Iso- 0 0 49 69 propanol) rate at point 7, kg/hr

The analytical properties of the silicon-treated carbon black areprovided in Table 7. The various formulations and the mixing procedureused to produce the rubber compound using these silicon-treated carbonblacks are described in Tables 8 and 9. The performance of thesilicon-treated carbon blacks are described in Table 10. It is seen thatthe aggregates of the present invention made using the process describedabove result in a 6-10% improvement (compared to conventional carbonblack) in wet skid resistance as measured by the British Portable SkidTester.

TABLE 7 Analytical Properties of Carbon Blacks as is BET of BET areat-area CDBP ash, Filler % Si m²/g m²/g ml/100 g m²/g N234 0.02 122.2120.4 103 N/A MPCS-1 14.8 154.2 122.7 103.8 437 MPCS-2 8.1 149 124.1102.8 504 MPCS-3 8.2 152.6 124.7 105 601 MPCS-4 4.9 142.9 126.5 103.4579 MPCS-5* 4.8 154.3 121.4 100.3 725 *MPCS-5 made by introducing allcarbon black-yielding feedstock and all silicon-containing compound into only first stage of the reactor.

TABLE 8 Analytical Properties of Carbon Blacks after HF treatment BETarea t-area Filler m²/g m²/g % silica ash N234 121.7 122.2 0.02 MPCS-1166.9 149.4 0.36 MPCS-2 157.9 142.1 0.31 MPCS-3 159.7 150.4 0.17 MPCS-4143.6 136.6 0.07 MPCS-5* 310.1 154.8 1.50

TABLE 9 Formulation N234 D4-CB SSBR (Duradene 715) 75 75 BR (Tacktene1203) 25 25 N234 80 — MPCS filler — 80 Si 69 — variable Oil (Sundex8125) 32.5 32.5 Zinc Oxide 3.5 3.5 Stearic Acid 2 2 Antioxident(Flexzone 7P) 2 1.5 Wax (Sunproof Improved) 2.5 1.5 Durax ® 1.35 1.5Vanax ® DPG — 0.5 TBzTD — 0.25 Sulfur 1.35 1.4 TBzTD - accelerator,tetrabenzyl thiuram disulfide, from Uniroyal Chemical Co. Middlebury, CT

TABLE 10 Mixing Procedure for Tread Compounds of Passenger Tire Stage 1Brabender Plasti-corder EPL-V. 60 rpm, 80° C., air on, start all mixes @100° C. 0′ Add polymer 1′ Add filler, coupling agents (Preblended) @160°C. Add oil. 7′ @165° C. Dump. Pass through open mill 3 times. Sit atroom temperature for at least 2 hrs. Stage 2 60 rpm, 80° C., air on,start all mixes @ 100° C. 0′ Add masterbatch from stage 1. 1′ Add ZnO,Stearic acid. 3′ Add Flexzone 7P and Wax. 4′, @165° C. Dump Pass throughopen mill 3 times. Sit at room temperature for at least 2 hrs. Stage 335 rpm, 80° C. air on, start all mixes @ 100° C. 0′ Add masterbatch fromstage 2. 1′ Add curatives. 2′ Dump. Pass through open mill 3 times.

TABLE 11 Physical Properties of Vulcanizates Si 69 Wet skid Tan 8 FillerPhr Resistance, % @ 70° C. N234 0 100 0.325 MPCS-1 3.2 110 0.163 MPCS-22.4 107 0.192 MPCS-3 2.4 107 0.149 MPCS-4 2.0 106 0.190 MPCS-5 2.0 1030.168

As seen in the above Tables, the samples of the present invention hadbetter properties, such as improved skid resistance over elastomericcompositions containing multi-phase aggregates made using a single stageaddition.

Other embodiments of the present invention will be apparent to thoseskilled in the art from consideration of the specification and practiceof the invention disclosed herein. It is intended that the specificationand examples be considered as exemplary only, with a true scope andspirit of the invention being indicated by the following claims.

What is claimed is:
 1. An elastomeric composition comprising at leastone elastomer, an aggregate, and optionally a coupling agent, saidaggregate comprising a carbon phase and a silicon-containing speciesphase, wherein said aggregate has at least one of the followingcharacteristics: a) a difference between BET (N₂) surface area andexternal surface area of from about 2 to about 100 m²/g; b) a differencebetween BET (N₂) surface area and external surface area of from about 1to about 50 m²/g after hydrofluoric acid treatment; c) a ratio of fromabout 0.1 to about 10 based on 1) the m²/g difference in BET (N₂)surface area between the aggregate after and before hydrofluoric acidtreatment to 2) weight percentages of elemental silicon content in saidaggregate without hydrofluoric acid treatment; d) a weight averageaggregate size measured by Disc centrifuge photosedimentameter afterhydrofluoric acid treatment is reduced by about 5% to about 40% comparedto weight average aggregate size without hydrofluoric acid treatment; e)a silica ash content in said aggregate of from about 0.05% to about 1%based on the weight of said aggregate after hydrofluoric acid treatmentand based on ash resulting from silicon-containing compound; and f) aBET surface area of silica ash in said aggregate of from about 200 m²/gto about 700 m²/g.
 2. The elastomeric composition of claim 1, whereinsaid elastomer comprises natural rubber, polyisoprene, polybytadine,emulsion SBR, solution SBR, functionalized SBR, NBR, butyl rubber, EPDM,EPM, or homo- or co-polymers based on or containing 1,3 butadiene,styrene, isoprene, isobutylene, 2,3-dimethyl-1,3-butadiene,acrylonitrile, ethylene, propylene, or derivatives thereof.
 3. Theelastomeric composition of claim 1, further comprising a curing agent,reinforcing filler, a coupling agent, processing aids, oil extenders,antidegradents, or combinations thereof.
 4. The elastomeric compositionof claim 1, further comprising silica, carbon black or mixtures thereof.5. The elastomeric composition of claim 1, further comprising silica,carbon black, modified carbon black having an attached organic group,modified silica, carbon black at least partially coated with silica, orcombinations thereof.
 6. The elastomeric composition of claim 1, whereinthe aggregate has attached at least one organic group.
 7. Theelastomeric composition of claim 1, further comprising an aggregatecomprising a carbon phase and a silicon-containing species phase, andhaving attached at least one organic group.
 8. The aggregate of claim 1,wherein the aggregate has attached at least one organic group.
 9. Theelastomeric composition of claim 1, wherein said elastomeric compositionhas low hysteresis at high temperature, wherein said high temperature isfrom 20 to 100° C.
 10. The elastomeric composition of claim 1, whereinsaid elastomeric composition has a low rolling resistance when used intire compounds.
 11. The elastomeric composition of claim 1, wherein saidelastomeric composition has an increase in wet skid resistance comparedto the same elastomeric composition containing carbon black.
 12. Theelastomeric composition of claim 1, wherein said elastomeric compositionhas an increase in wet skid resistance of greater than 3% compared tothe same elastomeric composition containing carbon black.
 13. Theelastomeric composition of claim 1, wherein said elastomeric compositionhas an increase in wet skid resistance of from greater than 3% to about20% compared to the same elastomeric composition containing carbonblack.
 14. A method of improving wet skid resistance in an elastomericcomposition comprising introducing the aggregate of claim 1 into theelastomeric composition.
 15. The method of claim 14, wherein the wetskid resistance increases at least greater than 3% compared to the sameelastomeric composition containing carbon black.
 16. The method of claim14, wherein the wet skid resistance increases at least 8% compared tothe same elastomeric composition containing carbon black.
 17. The methodof claim 14, wherein the wet skid resistance increases from at leastgreater than 3% to about 20% compared to the same elastomericcomposition containing carbon black.
 18. A method of improving therolling resistance in an elastomeric composition comprising introducingan aggregate into the elastomeric composition, wherein said aggregatecomprises a carbon phase and a silicon-containing species phase, whereinsaid aggregate has at least one of the following characteristics: a) adifference between BET (N₂) surface area and external surface area offrom about 2 to about 100 m²/g; b) a difference between BET (N₂) surfacearea and external surface area of from about 1 to about 50 m²/g afterhydrofluoric acid treatment; c) a ratio of from about 0.1 to about 10based on 1) the m^(2/) g difference in BET (N₂) surface area between theaggregate after and before hydrofluoric acid treatment to 2) weightpercentages of elemental silicon content in said aggregate withouthydrofluoric acid treatment; d) a weight average aggregate size measuredby Disc centrifuge photosedimentameter after hydrofluoric acid treatmentis reduced by about 5% to about 40% compared to weight average aggregatesize without hydrofluoric acid treatment; e) a silica ash content insaid aggregate of from about 0.05% to about 1% based on the weight ofsaid aggregate after hydrofluoric acid treatment and based on ashresulting from silicon-containing compound; and f) a BET surface area ofsilica ash in said aggregate of from about 200 m²/g to about 700 m²/g.